Service discovery

[b00lduck]

• DiscoveredBy decorator for fetch definitions
• discoveredBy attribute for tag
• fixed typos

[coveralls]

Coverage decreased (-1.3%) to 92.251% when pulling 39624d5 on service-discovery into 1cf43da on master.

[domano]

Remove the comments

[coveralls]

Coverage decreased (-1.3%) to 92.245% when pulling 04d322d on service-discovery into 1cf43da on master.

[coveralls]

Coverage decreased (-1.3%) to 92.245% when pulling 04d322d on service-discovery into 1cf43da on master.

[domano]

+1 (if the CI build succeeds ;) )

[coveralls]

Coverage decreased (-0.7%) to 92.852% when pulling 15d7ac1 on service-discovery into 1cf43da on master.

[coveralls]

Coverage decreased (-0.4%) to 93.122% when pulling cc53808 on service-discovery into 1cf43da on master.